Patient sensor intercommunication circuitry for a medical monitor

ABSTRACT

Systems, methods, and devices for intercommunication between a medical sensor and an electronic patient monitor are provided. For example, one embodiment of a system for communicably coupling a medical sensor to an electronic patient monitor may include a sensor-side communication connector and a monitor-side communication connector. The sensor-side communication connector may be capable of receiving a raw physiological measurement signal from the medical sensor, and the monitor-side communication connector may be capable of providing a digital physiological measurement signal based at least in part on the raw physiological measurement signal to the electronic patient monitor via a data link.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/872,501, entitled “AN OXIMETRY ASSEMBLY”, filed Apr. 29, 2013, whichis a continuation of U.S. Pat. No. 9,554,739, entitled “A SMART CABLEFOR COUPLING A MEDICAL SENSOR TO AN ELECTRONIC PATIENT MONITOR”,patented Jan. 31, 2017, which is herein incorporated by reference.

BACKGROUND

The presently disclosed subject matter relates generally tocommunicating data from a medical sensor to an electronic patientmonitor and, more particularly, to communicating physiologicalmeasurements from data or instructions for obtaining physiologicalmeasurements from data to an electronic patient monitor.

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present disclosure,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentdisclosure. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

Electronic patient monitors may be commonly used to monitor patientparameters such as ECG, pulse oximetry, blood pressure, and/or bodytemperature, among other things. Multi-parameter electronic patientmonitors may be expensive electronic patient monitor units that displaysuch patient parameters from a number of supported sensor types. Toaccommodate sensors from a variety of manufacturers, such monitors maybe designed to employ a proprietary connector for each sensor type. Thesensors may be attached to the monitor via the connector through apatient cable. The patient monitor may contain a dedicated circuit thatacquires data from the sensor and may include a special module thatspecializes in the type of sensor. For example, a multi-parametermonitor may contain an Original Equipment Manufacturer (OEM) module todetermine physiological measurements from a raw measurement. By way ofexample, within a single electronic patient monitor, a first OEM modulefrom a first manufacturer may receive a raw signal from aphotoplethysmographic sensor, determining pulse rate and/or oxygensaturation based on the raw signal. A second OEM module from a differentmanufacturer may receive a raw signal from a blood pressure cuff,determining blood pressure based on the raw signal.

The OEM modules in a multi-parameter monitor may be very difficult toupgrade, as the monitor may be disassembled before the OEM module isreplaced. Thus, it may be unlikely for major upgrades to a patientmonitor to occur once the patient monitor has been delivered to amedical facility. Accordingly, new developments, such as improvedalgorithms for obtaining physiological measurements from sensor data,may not easily be included in existing patient monitors. While someupgrades involve only firmware changes, the difficulty in upgrading isespecially relevant when hardware or connector changes are required. Inpractice, expensive monitors are seldom upgraded in the field.Typically, another device is placed next to the old monitor, resultingin cluttered hospital environments and multiple displays for thecaregivers to read. It may also be difficult to base alarm decisions onmultiple monitors since they typically do not communicate with eachother

SUMMARY

Certain aspects commensurate in scope with the originally claimedembodiments are set forth below. It should be understood that theseaspects are presented merely to provide the reader with a brief summaryof certain forms the embodiments might take and that these aspects arenot intended to limit the scope of the presently disclosed subjectmatter. Indeed, the embodiments may encompass a variety of aspects thatmay not be set forth below.

Present embodiments relate to systems, methods, and devices forintercommunicating medical sensors and electronic patient monitors. Forexample, one embodiment of a system for communicably coupling a medicalsensor to an electronic patient monitor may include a sensor-sidecommunication connector and a monitor-side communication connector. Thesensor-side communication connector may be capable of receiving a rawphysiological measurement signal from the medical sensor, and themonitor-side communication connector may be capable of providing adigital physiological measurement signal based at least in part on theraw physiological measurement signal to the electronic patient monitorvia a data link.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the presently disclosed subject matter may become apparentupon reading the following detailed description and upon reference tothe drawings in which:

FIG. 1 is a schematic diagram of a system having instructions for sensorprocessing in sensor-monitor communication circuitry, in accordance withan embodiment;

FIG. 2 is a block diagram of the system of FIG. 1, in accordance with anembodiment;

FIG. 3 is a more detailed block diagram of the system of FIG. 1, inaccordance with an embodiment;

FIG. 4 is a block diagram of a cable connection to a medical sensor, inaccordance with an embodiment;

FIG. 5 is a block diagram of a data link to a patient monitor, inaccordance with an embodiment;

FIG. 6 is a flowchart describing an embodiment of a method forprocessing sensor data in a patient cable;

FIG. 7 is a block diagram of an alternative system of FIG. 1, inaccordance with an embodiment;

FIG. 8 is a flowchart of an embodiment of a method for processing sensordata in a patient monitor based on instructions from a patient cable;

FIG. 9 is a block diagram of an alternative system for providing sensordata to a patient monitor, in accordance with an embodiment;

FIG. 10 is a block diagram describing the system of FIG. 9 in greaterdetail, in accordance with an embodiment;

FIG. 11 is a flowchart describing an embodiment of a method forupgrading firmware in a patient cable; and

FIGS. 12-17 are flowcharts describing embodiments of methods fordetermining a protocol for communication between a patient cable and apatient monitor.

DETAILED DESCRIPTION

One or more specific embodiments of the present disclosure will bedescribed below. In an effort to provide a concise description of theseembodiments, not all features of an actual implementation are describedin the specification. It should be appreciated that in the developmentof any such actual implementation, as in any engineering or designproject, numerous implementation-specific decisions must be made toachieve the developers' specific goals, such as compliance withsystem-related and business-related constraints, which may vary from oneimplementation to another. Moreover, it should be appreciated that sucha development effort might be complex and time consuming, but wouldnevertheless be a routine undertaking of design, fabrication, andmanufacture for those of ordinary skill having the benefit of thisdisclosure.

Present embodiments may apply to a variety of medical sensors, includingphotoplethysmographic sensors, temperature sensors, respiration bands,blood pressure sensors, electrocardiogram (ECG) sensors,electroencephalogram (EEG) sensors, pulse transit time sensors, and soforth. Such sensors may communicate with an electronic patient monitorusing intercommunication circuitry such as a patient cable or a wirelessconnection. According to embodiments disclosed herein, sensor-monitorintercommunication circuitry may include instructions for obtainingphysiological measurements from raw measurements. As such, an electronicpatient monitor may receive a signal over a data link using aproprietary or universal protocol from such intercommunicationcircuitry, despite that a specific OEM board may not necessarily beinstalled within the receiving monitor. For example, the patient cablemay transmit messages indicating the physiological measurements orprovide instructions for obtaining the physiological measurements to themonitor using a protocol that may be proprietary to the monitor.

As used in the present disclosure, “instructions” that may be used forobtaining physiological measurements may refer to any information thatenables the monitor to determine physiological characteristics of apatient from data collected by a medical sensor. Such instructions mayinclude executable code (e.g., software) written specifically for thehost processor of the monitor, or written to support any suitableprocessor type. The instructions could include a protocol whereby theprocessor is instructed to load such executable code and/or data memoryto an absolute or relative address in the processor's memory.Additionally or alternatively, the instructions could include a highlevel script, which may be a proprietary format or an open format (e.g.,Sun's JAVA language or Perl/Unix shell scripts), which is notprocessor-specific and which may instruct the processor to performcertain operations on the data.

With the foregoing in mind, FIG. 1 illustrates a perspective view of anembodiment of a sensor-monitor interconnection system 10 forcommunicably coupling an electronic patient monitor 12 to a medicalsensor 14. Although the embodiment of the system 10 illustrated in FIG.1 relates to photoplethysmography, the system 10 may be configured toobtain a variety of physiological measurements using a suitable medicalsensor. For example, the system 10 may, additionally or alternatively,be configured to obtain a respiration rate, a patient temperature, anECG, an EEG, a blood pressure, and/or a pulse transit time, and soforth.

The patient monitor 12 may communicate with the medical sensor 14 via ashort analog cable 18 coupled to a sensor-monitor intercommunicationcable 20. The patient monitor 12 may include a display 16, a memory, andvarious monitoring and control features. In certain embodiments, thepatient monitor 12 may include a processor configured to receivesoftware instructions from the sensor-monitor intercommunication cable20. The software instructions may be employed by the processor in thepatient monitor 12 to obtain physiological measurements, such as pulserate or blood oxygen saturation, from raw photoplethysmographic data orother raw data that has been digitized within the sensor-monitorintercommunication cable 20. In other embodiments, the patient monitor12 may not include a processor with such capabilities, but may rather beconfigured to display physiological measurements, such as pulse rate orblood oxygen saturation, that have been determined within thesensor-monitor intercommunication cable 20. For example, when the system10 is configured for photoplethysmography, the sensor-monitorintercommunication cable 20 may include software instructions and/orcapabilities for performing pulse oximetry measurements, calculations,and control algorithms, based on the sensor data received from themedical sensor 14.

In the presently illustrated embodiment of the system 10, the medicalsensor 14 is a photoplethysmographic sensor. As should be appreciated,however, the sensor 14 may be a photoplethysmographic sensor, atemperature sensor, a respiration band, a blood pressure sensor, anarrhythmia sensor, a pulse transit time sensor, or any other suitablemedical sensor. As noted above, the sensor 14 may include the shortanalog cable 18. The short analog cable 18 may include a sensorconnector 22 that joins to a sensor-side cable connector 24 of thesensor-monitor intercommunication cable 20. The analog cable 18 may beof a sufficiently short length to prevent excessive interference beforereaching the sensor-monitor intercommunication cable 20. Thesensor-monitor intercommunication cable 20 may include the sensor-sidecable connector 24, a monitor protocol selection button or switch 25,intercommunication cabling 26, and a monitor-side cable connector 28.The monitor-side cable connector 28 may join to a monitor connector 30with a data communication link, such as a serial peripheral interface(SPI), a universal serial bus (USB) interface, a universal asynchronousreceiver/transmitter (UART) interface, a Two Wire Interface (TWI) suchas I2C, or an RS232 interface, or any other suitable communication link.

As described in greater detail below, the sensor-monitorintercommunication cable 20 may communicate with the monitor 12 using aprotocol understandable by the monitor 12. Such protocols may include,for example, the Standard Host Interface Protocol (SHIP) or the PhillipsInterface Protocol (PIP). The sensor-monitor intercommunication cable 20may be preprogrammed to communicate using the protocol or mayautomatically select the particular protocol from among a variety ofpreprogrammed protocols, as described below with reference to FIGS. 12and 13. Additionally or alternatively, a practitioner may manually setthe protocol by pressing the button or switch 25 or selecting a settingon the button or switch 25. Thereafter, the sensor-monitorintercommunication cable 20 may communicate with the electronic patientmonitor 12 and may not need to be specific to particular vendors or toparticular sensors. Additionally or alternatively, the sensor-monitorintercommunication cable 20 may automatically negotiate a mutuallysupported protocol with the electronic patient monitor 12 or use othertechniques to determine such a protocol, as generally described belowwith reference to FIGS. 12-17.

A sensor assembly or body 32 of the wireless medical sensor 14 mayattach to patient tissue (e.g., a patient's finger, ear, forehead, ortoe). In the illustrated embodiment, the sensor assembly 32 isconfigured to attach to a finger. The medical sensor 14, illustrated inthe present embodiment as a photoplethysmographic sensor, may include anemitter 34 and a detector 36. When attached to pulsatile tissue of apatient 38, the emitter 34 may transmit light at certain wavelengthsinto the tissue and the detector 36 may receive the light after it haspassed through or is reflected by the tissue. The amount of light thatpasses through the tissue and other characteristics of light waves mayvary in accordance with the changing amount of certain bloodconstituents in the tissue and the related light absorption and/orscattering. For example, the emitter 34 may emit light from two or moreLEDs or other suitable light sources into the pulsatile tissue. Thereflected or transmitted light may be detected with the detector 36,such as a photodiode or photo-detector, after the light has passedthrough or has been reflected by the pulsatile tissue.

FIG. 2 is a simplified block diagram of the system 10 of FIG. 1. Asillustrated in FIG. 2, the sensor 14 may connect to the patient monitor12 by way of the sensor-monitor intercommunication cable 20. Inparticular, the sensor connector 22 of the analog cable 18 may connectto the sensor-side cable connector 24 of the sensor-monitorintercommunication cable 20. The sensor-side cable connector 24 mayreceive analog data from the medical sensor 14, digitize the data, andtransmit the digitized data to the monitor-side cable connector 28 viathe digital cable 26. One embodiment of the digital cable 26 may includeminimal interconnecting cabling, which may include, for example, twopower subcables and digital communication subcabling, as described belowwith reference to FIG. 4. It should be appreciated that the digitalcable 26 may employ any suitable power cabling structures and/ortechniques, and should not be understood to be limited to two powersubcables.

In alternative embodiments, the sensor-side cable connector 24 maytransmit the received analog data to the monitor-side cable connector 28without first digitizing the data. With such alternative embodiments,the monitor-side cable connector 28 may instead digitize the analogdata. If the sensor-side cable connector 24 does not first digitize theanalog data before transmitting the data to the monitor-side cableconnector 28, additional cabling and shielding may be employed toprevent attenuation and/or interference.

The monitor-side cable connector 28 may process the digitized data toobtain a physiological measurement, transmitting the determinedphysiological measurement to the patient monitor 12 via the monitorconnector 30. Alternatively, the monitor-side cable connector 28 maytransmit software instructions for obtaining the physiologicalmeasurements from the digitized data to the monitor 12. Thereafter, themonitor-side cable connector 28 may transmit the digitized data to themonitor 12 via the monitor connector 30, which may process the digitizeddata according to the received software instructions to obtainphysiological measurements.

As described below, the monitor-side cable connector 28 may communicatewith the monitor 12 via the monitor connector 30 using any suitableprotocol. For example, the monitor 12 may only communicate via a singleprotocol, such as Phillips Interface Protocol (PIP), and themonitor-side cable connector 28 may communicate using the PIP protocolafter automatically determining that messages sent to the monitor 12 betransmitted using the PIP protocol, as described below with reference toFIGS. 12-13, or after being manually set by a practitioner via thebutton or switch 25.

As described further below, the monitor-side cable connector 28 mayautodetect the protocol by, for example, sending a command in a givenprotocol and waiting for a valid response. If no valid response isreturned by the monitor 12 within a given time, and the monitor-sidecable connector 28 may continue trying other protocols until a messagetype is found to which the monitor 12 responds. After such an initialnegotiation, the monitor-side cable connector 28 may stay in thenegotiated protocol until power off. Additionally or alternatively, themonitor-side cable connector 28 may store the negotiated protocol in itsnon-volatile memory 62 and may remember the setting at next power up(reverting to negotiations only if the saved protocol fails).Additionally or alternatively, the monitor 12 may negotiate with themonitor-side cable connector 28. In some embodiments, the monitor 12 mayidentify its protocol at startup by sending a message type agreed on byseveral or all manufacturers of patient monitors. In some embodiments,certain connector pins may be connected to power or ground, or tospecific resistors or voltages, through which the monitor-side cableconnector 28 may identify the type of the monitor 12. Also, in someembodiments, the protocol may be determined during a USB deviceenumeration process.

The monitor connector 30 attached to the monitor 12 may represent acommunication data link capable of communicating via one or moreprotocols. As noted above, the monitor connector 30 may include a serialperipheral interface (SPI), a universal serial bus (USB) interface, auniversal asynchronous receiver/transmitter (UART) interface, a Two WireInterface (TWI) such as I2C, or an RS232 interface, or any othersuitable communication link. One embodiment of the pinout of the monitorconnector 30 is described in greater detail below with reference FIG. 5.

FIG. 3 is a more detailed block diagram of the system 10. By way ofexample, embodiments of the system 10 may be implemented with anysuitable medical sensor and patient monitor, such as those availablefrom Nellcor Puritan Bennett LLC. The system 10 may include the patientmonitor 12, the sensor 14, and the sensor-monitor intercommunicationcable 20, which may be configured to obtain, for example, aphotoplethysmographic signal from patient tissue at certainpredetermined wavelengths. The medical sensor 14 may be communicativelyconnected to the patient monitor 12 via the sensor-monitorintercommunication cable 20. When the system 10 is operating, light fromthe emitter 34, which may include one or more light emitting diodes(LEDs) of certain wavelengths, may pass into the patient 38 and bescattered and detected by the detector 36.

Specifically, the sensor 14 may be controlled by the signals from thesensor-side cable connector 24. A digital communication interface 40 mayreceive control signals from the monitor-side cable connection 28, whichmay control the manner in which sensor interface circuitry 42 controlsthe sensor 14. The sensor interface circuitry 42 may control the sensor14 using any suitable pulse oximetry technique. In some embodiments, atime processing unit (TPU) may provide timing control signals to lightdrive circuitry. Such light drive circuitry may drive the emitter 34,controlling when the emitter 34 is illuminated, and if multiple lightsources are used, the multiplexed timing for the different lightsources. The sensor interface circuitry 42 may also receive signals fromthe detector 36. The signals from the detector 36 may represent rawanalog data, which may be digitized by the sensor interface circuitry42. In some embodiments, the sensor interface circuitry 42 may include,for example, an amplifier, a filter, and an analog to digital (A/D)converter circuit. The sensor interface circuitry 42 may sample thesesignals at the proper time, depending upon which of multiple lightsources is illuminated, if multiple light sources are used. The sampledsignals represent digitized raw data that may be, for example, a raw16-bit digital stream of photoplethysmographic data sampled at 100 Hz.

In an embodiment, the sensor 14 may also contain an encoder 48 thatprovides signals indicative of the wavelength of one or more lightsources of the emitter 34, which may allow for selection of appropriatecalibration coefficients for calculating a physiological parameter suchas blood oxygen saturation. The encoder 48 may, for instance, be a codedresistor, EEPROM or other coding devices (such as a capacitor, inductor,PROM, RFID, parallel resonant circuits, or a colorimetric indicator)that may provide a signal related to the characteristics of the medicalsensor 14 that may indicate appropriate calibration characteristics forthe photoplethysmographic sensor 14. Further, the encoder 48 may includeencryption coding that prevents a disposable part of thephotoplethysmographic sensor 14 from being recognized by a processor 38that is not able to decode the encryption. For example, adetector/decoder 50 may be required to translate information from theencoder 48 before it can be properly processed to obtain physiologicalmeasurements from the digitized raw data output by the sensor interfacecircuitry 42.

Digital data from the detector/decoder 50 and/or the sensor interfacecircuitry 42 may be sent to the digital communication interface 40.Additionally, if present, the button or switch 25 may provide digitalinformation to the digital communication interface 40 indicating theparticular protocol with which the sensor-monitor intercommunicationcable 20 should use to communicate with the electronic patient monitor12. The digital communication interface 40 may coordinate thetransmission of the digital data to the monitor-side cable connector 28.The digital data may be transmitted over the digital cable 26 andreceived by another digital communication interface 52 using anysuitable protocol. For example, the digital communication interfaces 40and 52 may communicate using, for example, a serial peripheral interface(SPI), a universal serial bus (USB) interface, a universal asynchronousreceiver/transmitter (UART) interface, a Two Wire Interface (TWI) suchas I2C, or an RS232 interface. The digital data may be provided to a bus54 connected to a microprocessor 56.

In various embodiments, based at least in part upon the value of thereceived digitized raw data corresponding to the light received bydetector 36, the microprocessor 56 may calculate a physiologicalparameter of interest using various algorithms. These algorithms mayutilize coefficients, which may be empirically determined, correspondingto, for example, the wavelengths of light used. The algorithms may storeinterim values and other digital data in RAM 58. The algorithms andother software instructions for obtaining a physiological measurementbased on the digitized data may be stored in ROM 60 or nonvolatilestorage 62, which may include, for example, Flash memory. In atwo-wavelength system, the particular set of coefficients chosen for anypair of wavelength spectra may be determined by the value indicated bythe encoder 48 corresponding to a particular light source provided bythe emitter 34. For example, the first wavelength may be a wavelengththat is highly sensitive to small quantities of deoxyhemoglobin inblood, and the second wavelength may be a complimentary wavelength.Specifically, for example, such wavelengths may be produced by orange,red, infrared, green, and/or yellow LEDs. Different wavelengths may beselected based on instructions from the patient monitor 12, preferencesstored in a nonvolatile storage 62. Such instructions or preferences maybe selected at the patient monitor 12 by a switch on the patient monitor12, a keyboard, or a port providing instructions from a remote hostcomputer. Other software or instructions for carrying out the techniquesdescribed herein may also be stored on the nonvolatile memory 62, or maybe stored on the ROM 60. The physiological measurements determined inthe sensor-monitor intercommunication cable 20 may be encoded in a firstprotocol, which may or may not be proprietary to the sensor-monitorintercommunication cable 20. As described below, the physiologicalmeasurements may be translated from the first protocol into a secondprotocol understandable to the monitor 12, if the monitor 12 is notcapable of understanding the first protocol.

After determining physiological measurements based on the receiveddigitized raw data, the microprocessor 56 may communicate with themonitor 12 via a cable-monitor interface 64. The cable-monitor interface64 may transmit these physiological measurements and/or the digitizedraw data to the monitor 12 via the monitor connector 30. Thesensor-monitor intercommunication cable 20 may communicate usingmessages in a protocol understandable by the electronic patient monitor12. The protocol may be indicated by a selection made by the button orswitch 25, or may be determined automatically by the sensor-monitorintercommunication cable 20, as described below with reference to FIGS.12 and 13. In this way, the sensor-monitor intercommunication cable 20may not need to be specific to a manufacturer or vendor.

It should be appreciated that the configuration of the sensor-monitorintercommunication cable 20 illustrated in FIG. 3 may vary. For example,certain circuitry of the sensor-side cable connector 24 may beincorporated into the monitor-side cable connector 28. If the sensorinterface circuitry 42 is incorporated into the monitor-side cableconnector 28, the cable 26 may transmit analog signals rather thandigital signals, and additional shielding may be used to reduceattenuation and/or interference. Similarly, certain circuitry of themonitor-side cable connector 28 may be incorporated into the sensor-sidecable connector 24, such as the microprocessor 56. If the microprocessor56 is incorporated into the sensor-side cable connector 24, thesensor-side cable connector may have the capability to determinephysiological measurements from the digitized data, which may betransmitted over the digital cable 26. In certain other embodiments, allor part of the circuitry of the sensor-monitor intercommunication cable20 may be incorporated into the medical sensor 14. However, if themedical sensor 14 is a replaceable sensor, incorporating such circuitryinto the sensor 14 may be costly. Moreover, as described below withreference to FIGS. 9 and 10, circuitry with the capabilities describedabove may be incorporated into other intercommunication links betweenthe sensor 14 and the electronic patient monitor. For example, thecircuitry may be incorporated into a separable cable connector ordongle, or into wireless adapters for joining the medical sensor 14 andthe patient monitor 12.

FIG. 4 illustrates an exemplary configuration of an embodiment of thedigital cable 26 between the sensor-side cable connector 24 and themonitor-side cable connector 28. Specifically, the digital cable 26 mayinclude power, such as a 5V supply 66 in one particular embodiment, aground line 68, and one or more digital communication lines 70. Thedigital communication lines may employ any suitable protocol forintercommunication of digital data between the sensor-side cableconnector 24 and the monitor-side cable connector 28. For example, asnoted above, such protocols may include serial peripheral interface(SPI), universal serial bus (USB), universal asynchronousreceiver/transmitter (UART), a Two Wire Interface (TWI) such as I2C, orRS232 protocols.

The digital cable 26 may carry signals over the longest distance of thesensor-monitor intercommunication cable 20. By transmitting digitalsignals rather than analog, the digital cable 26 may not require as muchshielding as a cable for transmitting an analog signal. Though somecable shielding may be employed to reduce electromagnetic emissions fromthe cable 26, the digitized signals may be much less likely to becorrupted by electromagnetic noise than low amplitude sensor outputs.Moreover, digital errors over the digital cable 26 may be detected,corrected, or may trigger data re-transmission in communications betweenthe sensor-side cable connector 24 and the monitor-side cable connector28.

FIG. 5 illustrates an exemplary configuration of an embodiment of thepinout interconnections between the cable-monitor interface 64 of themonitor-side cable connector 28 and the monitor connector 30. The pinoutconfiguration may employ any suitable protocol for intercommunication ofdigital data between the cable-monitor interface 64 and the monitorconnector 30. For example, as noted above, such protocols may includeserial peripheral interface (SPI), universal serial bus (USB), universalasynchronous receiver/transmitter (UART), a Two Wire Interface (TWI)such as I2C, or RS232 protocols.

In the instant exemplary configuration, the pinout configuration mayinclude a 5V line 72, a ground line 74, and various signal interfacescorresponding to serial peripheral interface (SPI) pins. These mayinclude a synchronous clock (SCK) 76 pin, a master input/slave output(MISO) 78 pin, a master output/slave input (MOSI) 80 pin, and a chipselect (CS) pin 82. The SCK 76 may provide a serial clock input from thepatient monitor 12 to the sensor-monitor intercommunication cable 20.The MISO 78 may transmit synchronous serial data, such as physiologicalmeasurements determined in the monitor-side cable connector 28, from thesensor-monitor intercommunication cable 20 to the patient monitor 12.The MOSI 80 may transmit synchronous serial data, such as sensor controlsignals, from the patient monitor 12 to the sensor-monitorintercommunication cable 20. The patient monitor 12 may use the CS 82 toelect to communicate with the sensor-monitor intercommunication cable20. To reduce pin count, the CS signal 82 may be omitted from theconnector and tied to ground (active low) at the slave side if there isonly one master and one slave on the bus. The cable may be designed suchthat either the monitor 12 or the sensor-monitor intercommunicationcable 20 is the SPI bus master. In this way, the configurationillustrated in FIG. 5 may enable the patient monitor 12 to control anumber of different sensors 14 coupled via similar SPI configurationsand sensor-monitor intercommunication cables 20.

FIG. 6 is a flowchart 84 describing an embodiment of a method forcommunicably coupling the medical sensor 14 to the patient monitor 12via the sensor-monitor intercommunication cable 20. In particular, theembodiment of the method of the flowchart 84 contemplates asensor-monitor intercommunication cable 20 that includes themicroprocessor 56, as well as appropriate software instructions storedwithin the ROM 60 or the nonvolatile memory 62. Because thesensor-monitor intercommunication cable 20 includes the processor 56,the patient monitor 12 need not include a processor capable ofextracting physiological measurements based on data from the sensor 14.Rather, the patient monitor 12 may require only the capability todisplay data received from the sensor-monitor intercommunication cable20. The flowchart 84 may be carried out using the embodiment of FIG. 3,as well as embodiments with similar capabilities, such as thosedescribed below with reference to FIGS. 9 and 10.

In a first step 86, the sensor-monitor intercommunication cable 20 mayobtain analog raw data from the sensor 14. Depending on the medicalsensor 14, such analog data may include, for example,photoplethysmographic data, temperature data, respiration data, bloodpressure data, arrhythmia data, ECG data, pulse transit time data, andso forth. By way of example, the analog raw data may be received by thesensor-side cable connector 24. In step 88, the raw analog data may bedigitized by the sensor-monitor intercommunication cable 20 to obtaindigitized raw data. If the analog raw data is a photoplethysmographicsignal, the digitized raw data may be, for example, a raw 16-bit digitalstream of photoplethysmographic data sampled at 100 Hz. Suchdigitization may take place via the sensor interface circuitry 42 in thesensor-side cable connector 24.

In step 90, the sensor-monitor intercommunication cable 20 may convertthe digitized raw data into physiological measurements. By way ofexample, if the digitized raw data is photoplethysmographic data, thephysiological measurements may include pulse rate, blood oxygensaturation, and/or total hemoglobin measurements. The physiologicalmeasurements may be obtained by the processing the digitized raw datausing the microprocessor 56, according to instructions stored in the ROM60 or nonvolatile memory 62. These physiological measurements may betransmitted to the patient monitor 12 in step 92, and displayed on thepatient monitor 12 in step 94. The sensor-monitor intercommunicationcable 20 may communicate with the electronic patient monitor 12 usingmessages of a protocol understandable by the electronic patient monitor12. The protocol may be indicated by a selection made by the button orswitch 25, or may be determined automatically by the sensor-monitorintercommunication cable 20, as described below with reference to FIGS.12 and 13. In this way, the sensor-monitor intercommunication cable 20may not need to be specific to a manufacturer or vendor.

In some embodiments, the physiological measurements obtained in step 90may be used to determine alarm status. For example, the patient monitor12 may indicate alarm limits for certain detectable physiologicalparameters to the sensor-monitor intercommunication cable 20. If thephysiological measurements obtained in step 90 exceed the alarm limits(e.g., if heart rate or SpO₂ exceed a predetermined range), thesensor-monitor intercommunication cable 20 may respond accordingly. Forexample, in step 92, the sensor-monitor intercommunication cable 20 maytransmit such an alarm to the patient monitor 12 in step 92.

As noted above, the circuitry and capabilities of the sensor-monitorintercommunication cable 20 may vary. FIG. 7 illustrates an alternativeembodiment of the system 10, in which the sensor-monitorintercommunication cable 20 is capable of digitizing sensor 14 data, butlacks the ability to process the digitized data into physiologicalmeasurements on its own. In particular, the embodiment of the system 10illustrated in FIG. 7 may be substantially identical to the embodimentof the system 10 illustrated in FIG. 3, except that the monitor-sidecable connector 28 may lack the microprocessor 56 and/or RAM 58. Whenused with a patient monitor 12 having a suitable processor, however, thesensor-monitor intercommunication cable 20 may provide the patientmonitor 12 with software instructions for obtaining such physiologicalmeasurements. Such instructions may be stored, for example, in the ROM60 or the nonvolatile memory 62. After receiving the softwareinstructions from the sensor-monitor intercommunication cable 20, thepatient monitor 12 may thereafter obtain the physiological measurementsbased on digitized raw data received from the sensor-monitorintercommunication cable 20.

A flowchart 96, illustrated in FIG. 8, describes an embodiment of amethod for processing medical sensor 14 data in the patient monitor 12using software instructions provided by the sensor-monitorintercommunication cable 20. The embodiment of the method of theflowchart 96 may be performed using either of the embodiments of thesensor-monitor intercommunication cable 20 described in FIG. 3 or FIG.7, as well as the embodiments of similar circuitry with similarcapabilities described below with reference to FIGS. 9 and 10. Theelectronic patient monitor 12 should include a processor capable ofobtaining physiological measurements from digitized raw data, whenprovided the appropriate software.

In a first step 98, the sensor-monitor intercommunication cable 20 maysend software instructions for obtaining physiological measurements fromraw data, which may be in the form of firmware or a driver, to theelectronic patient monitor 12. Step 98 may take place, for example, whenthe electronic patient monitor boots up from an SPI flash memory device,or boot memory, located in the sensor-monitor intercommunication cable20. In step 100, the sensor-monitor intercommunication cable 20 mayreceive analog raw data from the sensor 14, in generally the same manneras described with reference to step 86 of the flowchart 84. In step 102,the raw analog data may be digitized by the sensor-monitorintercommunication cable 20 to obtain digitized raw data, in generallythe same manner as described with reference to step 88 of the flowchart84.

In step 104, the digitized raw data may be transmitted to the electronicpatient monitor 12 in a particular protocol understandable to themonitor 12. A practitioner may select the protocol via the button orswitch 25, the sensor-monitor intercommunication cable 20 may bepreprogrammed to communicate using the protocol, or the sensor-monitorintercommunication cable 20 may automatically select the properprotocol, as described below with reference to FIGS. 12 and 13. Usingthe firmware or driver received in step 98, in step 106, the monitor 12may process the digitized raw data to obtain physiological measurements,such as pulse rate, blood oxygen saturation, and/or a measurement oftotal hemoglobin. In step 108, the patient monitor 12 may display thephysiological measurements on the display 16.

FIGS. 9 and 10 represent alternative systems for intercommunicationbetween the medical sensor 14 and the electronic patient monitor 12. Inparticular, FIG. 9 illustrates a system employing the techniquesdescribed herein using an additional cable connector with memory orprocessing circuitry, and FIG. 10 illustrates a system employing thetechniques described herein using wireless communication in place of thedigital cable 26. Turning first to FIG. 9, a system 110 forintercommunication between the medical sensor 14 and the patient monitor12 may include a digitizing cable 112 coupled to the sensor connector 22of the analog cable 18. The digitizing cable 112 may include thesensor-side cable connector 24, which may be configured in the mannersdescribed above. Rather than include a monitor-side cable connector 28with memory or processing circuitry, the digitizing cable may include adumb connector 114 that may only transfer digital signals in the mannerreceived from the sensor-side cable connector 24. Thus, the digitizingcable 112 may simply digitize analog raw data received from the medicalsensor 14 into digital raw data.

In contrast, a smart connector 116 may include memory circuitry and/orprocessing circuitry for obtaining physiological measurements fromdigitized raw data. As such, the smart connector 116 may includesubstantially the same circuitry as the monitor-side cable connector 28,as illustrated in FIG. 3 or 7. The smart connector 116 may couple to thedumb connector 114 of the digitizing cable 112 using any suitable mannerto supply power to and exchange digital communication with thedigitizing cable 112. In general, the smart connector 116 mayinterconnect with the dumb connector 114 in substantially the same wayas the monitor-side cable connector 28 with the monitor connector 30 inthe system 10. The smart connector 116 may interconnect with the monitorconnector 30 in much the same way. As such, the smart connector 116 mayemploy a digital communication interface such as a serial peripheralinterface (SPI), a universal serial bus (USB) interface, a universalasynchronous receiver/transmitter (UART) interface, or an RS232interface, or any other suitable communication link. In particular, theinterface between the smart connector 116 and the monitor connector 30may be a data link.

FIG. 10 illustrates a sensor-monitor intercommunication link system 118for intercommunication between the medical sensor 14 and the patientmonitor 12 that may include wireless communication circuitry.Functioning largely like the system 10, the system 118 may includesensor-monitor wireless communication link 120 in place of thesensor-monitor intercommunication cable 20. A sensor-side wirelessadapter 122 may establish wireless communication 124 with a monitor-sidewireless adapter 126 using any suitable protocol. By way of example, theprotocol may include the IEEE 802.15.4 standard, and may employ, forexample, the ZigBee, WirelessHART, or MiWi protocols. Additionally oralternatively, the protocol may include the Bluetooth standard or one ormore of the IEEE 802.11 standards. In some embodiments, the wirelesscommunication 124 may include optical communication, such as free spaceoptics (FSO).

The sensor-side wireless adapter 122 and the monitor-side wirelessadapter 126 may include substantially the same circuitry as thesensor-side cable connector 24 and the monitor-side cable connector 28,respectively, except that the digital communication interfaces 40 and 52may be configured for wireless communication and may include one or morerechargeable or replaceable batteries. The monitor-side wireless adapter126 may couple to the monitor connector 30 in the same manner as themonitor-side cable connector 28 or the smart connector 116. It should beunderstood that the wireless interface may, additionally oralternatively, form part of the monitor 12. With such embodiments, theexternal connector 30 may be omitted. Also, in some embodiments, thesensor 14 may employ a single microcontroller without connector 22,whereby the microcontroller may sample the data obtained by the sensorand may also provide the processing required for wireless communication.

Like the system 10 discussed above, the systems 110 of FIG. 9 and 118 ofFIG. 10 may similarly enable rapid dispersion of improvements in sensor14 processing techniques that may otherwise require an upgraded OEMmodule for the patient monitor 12. Thus, rather than supply a new OEMmodule, a vendor may supply a sensor-monitor intercommunication cable20, a smart connector 116, or a monitor-side wireless adapter 126 withupgraded circuitry. The new sensor-monitor intercommunication cable 20,smart connector 116, or monitor-side wireless adapter 126 may be capableof processing digitized data to obtain physiological measurements or ofproviding such instructions to the patient monitor 12, as describedabove.

In certain embodiments of the systems 10, 110, or 118, thesensor-monitor intercommunication cable 20, smart connector 116, ormonitor-side wireless adapter 126 may be upgradeable via softwareupdates from a networked electronic patient monitor. FIG. 11 is aflowchart 128 illustrating one embodiment of a method for upgrading asensor-monitor intercommunication cable 20, smart connector 116, ormonitor-side wireless adapter 126. In a first step 130, softwareupdates, such as firmware or driver updates, may be downloaded onto anetworked electronic patient monitor 12. In step 132, the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 may be attached to the electronic patient monitor12. In step 134, the electronic patient monitor may upload the firmwareor driver to the nonvolatile memory 62 of the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126. It should be understood that the software upgradesprovided in the flowchart 128 may enable various additional oralternative methods for determining the physiological parameters fromthe digital raw data. Additionally or alternatively, the softwareupgrades may enable the sensor-monitor intercommunication cable 20,smart connector 116, or monitor-side wireless adapter 126 to send and/orreceive messages in a particular medical messaging protocol. It shouldfurther be understood that the flowchart 128 may alternatively becarried out by connecting the sensor-monitor intercommunication cable20, smart connector 116, or monitor-side wireless adapter 126 to aspecial- or general-purpose computer rather than the electronic patientmonitor 12.

As noted above, the sensor-monitor intercommunication cable 20, smartconnector 116, or monitor-side wireless adapter 126 may communicate withthe electronic patient monitor 12 using a specific protocol, such as theStandard Host Interface Protocol (SHIP) or the Phillips InterfaceProtocol (PIP). The specific protocol may be selectable by apractitioner via, for example, the button or switch 25 or by programmingthe cable with particular firmware or drivers. Additionally oralternatively, the monitor 12, the sensor-monitor intercommunicationcable 20, smart connector 116, or monitor-side wireless adapter 126 mayautomatically select the proper protocol for communication with theelectronic patient monitor 12. FIGS. 12-17 are flowcharts representingembodiments of methods for automatically selecting such a protocol foruse in the sensor-monitor intercommunication cable 20, smart connector116, or monitor-side wireless adapter 126.

Specifically, FIG. 12 is a flowchart 136 representing an embodiment of amethod for automatically selecting a protocol in the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 based on an initialization message from theelectronic patient monitor 12. In a first step 138, the monitor 12 maybe initialized. During an initialization procedure, the monitor 12 maysend one or more initialization messages to each of the sensors that maybe coupled to the monitor 12 in step 140. After receiving theinitialization messages in step 140, in step 142, the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 may determine the protocol in which theinitialization message is encoded. The determination of step 142 mayinvolve, for example, a comparison of initialization messages of variousprotocols stored in the ROM 60 or the nonvolatile memory 62, or ananalysis of the syntax or semantics of the initialization message. Afterthe protocol of the monitor 12 has been determined in step 142, thesensor-monitor intercommunication cable 20, smart connector 116, ormonitor-side wireless adapter 126 may store the determined protocol inthe RAM 58 or the nonvolatile storage 62. Thereafter, the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 may communicate with the electronic patient monitor12 using a protocol that the electronic patient monitor understands.

Similarly, FIG. 13 is a flowchart 146 representing an embodiment of amethod for automatically selecting a protocol in the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 based on the response to messages sent using avariety of protocols. In a first step 148, the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 may be connected to the electronic patient monitor12. The sensor-monitor intercommunication cable 20, smart connector 116,or monitor-side wireless adapter 126 may transmit a test message in afirst protocol in step 150. By way of example, the first protocol may bethe Standard Host Interface Protocol (SHIP).

As illustrated by a decision block 152, if the electronic patientmonitor 12 does not understand the first protocol, the electronicpatient monitor 12 may not respond or may respond with an error message.If so, after a timing-out period, in step 154, the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 may send a second test message in a secondprotocol. By way of example, the second protocol may be the PhillipsInterface Protocol (PIP).

Returning to the decision block 152, if the electronic patient monitor12 does understand the second protocol, the electronic patient monitor12 may respond with a message other than an error message. If so, instep 156, the sensor-monitor intercommunication cable 20, smartconnector 116, or monitor-side wireless adapter 126 may store theprotocol that achieved a non-error message response from the monitor 12in the RAM 58 or nonvolatile storage 62. On the other hand, if theelectronic patient monitor 12 does not understand the second protocol,the sensor-monitor intercommunication cable 20, smart connector 116, ormonitor-side wireless adapter 126 may continue to send test messages invarious protocols, which may be preprogrammed in the ROM 60 ornonvolatile storage 62, until the electronic patient monitor 12 respondsfavorably.

The sensor-monitor intercommunication cable 20, smart connector 116, ormonitor-side wireless adapter 126 may discern whether a response fromthe electronic patient monitor 12 is valid in any suitable manner. Forexample, the sensor-monitor intercommunication cable 20, smart connector116, or monitor-side wireless adapter 126 may send test messages inevery protocol preprogrammed in ROM 60 or nonvolatile storage 62 andstore the responses from the monitor 12. If certain responses differfrom other responses, and particularly if one response is different fromall other responses, the sensor-monitor intercommunication cable 20,smart connector 116, or monitor-side wireless adapter 126 may determinethat the other responses are error messages and the differentresponse(s) is a normal response. Alternatively, the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 may compare the responses as they arrive to storederror messages in the ROM 60 or nonvolatile storage 62 to determine whatresponses from the electronic patient monitor 12 are normal responsesindicating that the monitor 12 understands the protocol of the testmessage and which responses are error messages indicating that themonitor 12 does not understand the protocol of the test message. In someembodiments, the sensor-monitor intercommunication cable 20 may send anintentionally errored message to the monitor 12. The protocol of themonitor 12 can be narrowed down based on whether the monitor 12 repliesto errored messages and/or the format of the response. Certain protocols(e.g. SHIP) may have one or more SYNC byte(s) to start a message andcyclic redundancy check (CRC) for error checking, which may reduceambiguity in determining whether a message from the monitor 12 is valid.

FIG. 14 is a flowchart 158 representing an embodiment of a method forautomatically selecting a protocol in the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 based on the response to messages sent using avariety of protocols. In a first step 160, the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 may be connected to the electronic patient monitor12. In step 162, the sensor-monitor intercommunication cable 20, smartconnector 116, or monitor-side wireless adapter 126 may recall the mostrecently negotiated protocol, which may have been stored in non-volatilestorage 62. The sensor-monitor intercommunication cable 20, smartconnector 116, or monitor-side wireless adapter 126 may transmit a testmessage in the recalled protocol in step 164. Thereafter, decision block166 and steps 168 and 170 may take place in substantially the samemanner as decision block 152 and steps 154 and 156 of the flowchart 146of FIG. 13.

FIG. 15 is a flowchart 172 representing an embodiment of a method forautomatically selecting a protocol in the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 based on a configuration message from the patientmonitor 12. In a first step 174, the sensor-monitor intercommunicationcable 20, smart connector 116, or monitor-side wireless adapter 126 maybe connected to the electronic patient monitor 12. In step 176, thepatient monitor 12 may provide a configuration message. Theconfiguration message may be provided in a format that was previouslyagreed upon by many or all manufacturers of patient monitors 12. Themessage may indicate various information regarding the operation of thepatient monitor 12, including the communication protocol employed by thepatient monitor 12. In step 178, the sensor-monitor intercommunicationcable 20, smart connector 116, or monitor-side wireless adapter 126 maystore the protocol indicated by the configuration message from themonitor 12 in the RAM 58 or nonvolatile storage 62.

FIG. 16 is a flowchart 180 representing an embodiment of a method forautomatically selecting a protocol in the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 based on a connector 18 pin identification codefrom the patient monitor 12. In a first step 182, the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 may be connected to the electronic patient monitor12. In some embodiments, certain pins of the connecter 18 of the patientmonitor 12 may be connected to power or ground, or to specific resistorsor voltages, which may uniquely identify the type of the patient monitor12 or the protocol employed by the patient monitor 12. For suchembodiments, in step 184, sensor-monitor intercommunication cable 20,smart connector 116, or monitor-side wireless adapter 126 may detectsuch a connector 18 pin identification code that may identify thecommunication protocol employed by the patient monitor 12. In step 186,the sensor-monitor intercommunication cable 20, smart connector 116, ormonitor-side wireless adapter 126 may store the protocol indicated bythe connector 18 pin identification code from the monitor 12 in the RAM58 or nonvolatile storage 62.

FIG. 17 is a flowchart 188 representing an embodiment of a method forautomatically selecting a protocol in the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 based on a USB device enumeration process. As notedabove, in some embodiments, the sensor-monitor intercommunication cable20, smart connector 116, or monitor-side wireless adapter 126 may beconnected to the electronic patient monitor 12 via a USB connection.Such embodiments, as noted step 190, may be attached to the patientmonitor 12. A USB device enumeration process may ensue. In step 192,based on information retrieved from the patient monitor 12 during theUSB device enumeration process, the type of patient monitor 12 may beidentified. With knowledge of the type of the patient monitor 12, thesensor-monitor intercommunication cable 20, smart connector 116, ormonitor-side wireless adapter 126 may identify the protocol employed bysuch type of patient monitor 12. Thus, in step 186, the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126 may store the protocol indicated by the USB deviceenumeration process into the RAM 58 or nonvolatile storage 62.

While many of the methods for determining the communication protocolgenerally have been described as taking place in the sensor-monitorintercommunication cable 20, smart connector 116, or monitor-sidewireless adapter 126, it should be understood that such methods may,additionally or alternatively, take place in the patient monitor 12.That is, the patient monitor 12 may perform those actions ascribed tothe sensor-monitor intercommunication cable 20, smart connector 116, ormonitor-side wireless adapter 126, to determine which communicationprotocol to employ.

In alternative embodiments, the sensor-monitor intercommunication cable20, smart connector 116, or monitor-side wireless adapter 126 maycommunicate with the electronic patient monitor 12 in other ways. Forexample, rather than communicate using a single protocol, thesensor-monitor intercommunication cable 20, smart connector 116, ormonitor-side wireless adapter 126 may communicate a single message usingseveral protocols, and the electronic patient monitor 12 may disregardmessages not encoded in the protocol it understands. Additionally oralternatively, the sensor-monitor intercommunication cable 20, smartconnector 116, or monitor-side wireless adapter 126 may outputinformation in a universal protocol not specific to a particular vendor,or may output raw information using a protocol such as serial peripheralinterface (SPI) or universal serial bus (USB).

While the embodiments set forth in the present disclosure may besusceptible to various modifications and alternative forms, specificembodiments have been shown by way of example in the drawings and havebeen described in detail herein. However, it should be understood thatthe disclosure is not intended to be limited to the particular formsdisclosed. The disclosure is to cover all modifications, equivalents,and alternatives falling within the spirit and scope of the disclosureas defined by the following appended claims.

What is claimed is:
 1. An oximetry assembly comprising: a cable assemblyincluding a proximal end and a distal end; an oximetry sensor located atthe distal end of the cable assembly, the oximetry sensor configured toattach to a finger and comprising at least one emitter and at least onedetector, the at least one emitter configured to transmit light at oneor more wavelengths into tissue, the at least one detector configured toreceive the light after the light passes through or is reflected by thetissue and to generate raw oximetry data based on the light received; ananalog-to-digital converter housed within the cable assembly andconfigured to receive the raw oximetry data from the oximetry sensor andto digitize the raw oximetry data into digital oximetry data; aconnector located at the proximal end of the cable assembly andconfigured to removably couple the cable assembly to a patient monitor;an actuatable structure disposed on the cable assembly and configured tobe actuated into a first configuration, wherein the actuatable structuregenerates a first signal indicative of a first selected protocol from agroup of communication protocols in response to a user input that placesthe actuatable structure in the first configuration, and the actuatablestructure comprises a button or a switch; and a processor housed withinthe cable assembly and programmed to communicate using the group ofcommunication protocols and to receive the digital oximetry data fromthe analog-to-digital converter, and the actuatable structure isconfigured to transmit the first signal indicative of the first selectedprotocol to the processor, and the processor is programmed to receivethe first signal from the actuatable structure and to use the firstselected protocol based on the first signal to transmit the digitaloximetry data to the patient monitor, and the group of communicationprotocols comprise instructions decodable by the processor and theselected protocol comprises instructions decodable by the processor andthe patient monitor.
 2. The oximetry assembly of claim 1, wherein theprocessor is-programmed to determine when the digital oximetry data isencoded in a second protocol that is different from the selectedprotocol, and wherein the processor is programmed to translate thedigital oximetry data from the second protocol to the selected protocolbased on the determination.
 3. The oximetry assembly of claim 1, whereinthe cable assembly further comprises circuitry storing instructions forcalculating oximetry measurements from digital oximetry data, andwherein the processor is programmed to read the instructions from thecircuitry and to use the instructions to calculate oximetry measurementsfrom the digital oximetry data received from the analog-to-digitalconverter.
 4. The oximetry assembly of claim 1, wherein the cableassembly comprises circuitry that is housed within the cable assemblyand that generates control signals to drive the at least one emitter ofthe oximetry sensor.
 5. The oximetry assembly of claim 1, wherein thedigital oximetry data includes blood oxygen saturation and pulse rate.6. The oximetry assembly of claim 1, wherein the processor comprises amicroprocessor and software programmed to perform one or both ofmeasurements or calculations to determine oxygen saturation and pulserate based on the digital oximetry data received from theanalog-to-digital converter.
 7. The oximetry assembly of claim 1,wherein the processor is programmed to download software updates from aremote source.
 8. The oximetry assembly of claim 1, wherein theactuatable structure is configured to be actuated into a secondconfiguration and generates a second signal indicative of a secondselected protocol from the group of communication protocols in responseto a second user input that places the actuatable structure in thesecond configuration, and the actuatable structure is configured totransmit the second signal to the processor, and the processor isprogrammed to receive the second signal and to use the second selectedprotocol to transmit the digital oximetry data to the patient monitorbased on the second signal.
 9. An oximetry assembly comprising: a cableassembly including a proximal end and a distal end; an oximetry sensorlocated at the distal end of the cable assembly, the oximetry sensorconfigured to attach to a finger and comprising at least one emitter andat least one detector, the at least one emitter configured to transmitlight at one or more wavelengths into tissue, the at least one detectorconfigured to receive the light after the light passes through or isreflected by the tissue and to generate raw oximetry data based on thelight received; an analog-to-digital converter housed within the cableassembly and configured to receive the raw oximetry data from theoximetry sensor and to digitize the raw oximetry data into digitaloximetry data; a connector located at the proximal end of the cableassembly, the connector configured to removably connect the oximetrysensor to a monitor and allow communication with the monitor through adata communication link; and a processor housed within the cableassembly, and programmed to: receive the digital oximetry data from theanalog-to-digital converter; send a first command in a first protocol tothe monitor; determine that the first protocol comprises instructionsdecodable by the monitor in response to receiving a valid response fromthe monitor based on the first command; and transmit the digitaloximetry data to the monitor using the first protocol when the processorreceives the valid response.
 10. The oximetry assembly of claim 9,further comprising circuitry housed within the cable assembly, thecircuitry stores instructions for determining oximetry measurements fromdigital oximetry data, and the processor is programmed to provide theinstructions to the monitor.
 11. The oximetry assembly of claim 9,wherein the oximetry sensor is controlled by the processor.
 12. Theoximetry assembly of claim 9, wherein the digital oximetry data includesblood oxygen saturation and pulse rate.
 13. The oximetry assembly ofclaim 9, wherein the processor comprises a microprocessor and softwareprogrammed to perform one or both of measurements or calculations todetermine oxygen saturation and pulse rate based on the digital oximetrydata received from the analog-to-digital converter.
 14. The oximetryassembly of claim 9, wherein the data communication link includes one ofa serial peripheral interface (SPI), a universal serial bus (USB)interface, a universal asynchronous receiver/transmitter (UART), a twowire interface (TWI), or an RS232 interface.
 15. The oximetry assemblyof claim 9, wherein the processor is programmed to download softwareupdates from a remote source.
 16. The oximetry assembly of claim 9,wherein the processor is programmed to send a second command in a secondprotocol to the monitor if a valid response is not received by theprocessor in response to the first command, to determine that the secondprotocol comprises instructions decodable by the monitor in response toreceiving a valid response from the monitor in response to the secondcommand, and to transmit the digital oximetry data to the monitor usingthe second protocol when the processor receives the valid response inresponse to the second command.
 17. The oximetry assembly of claim 9,wherein the oximetry assembly comprises a memory, and wherein theprocessor is programmed to store the protocol of the monitor determinedby the processor in the memory.